It's hard to imagine, but up until 1992, astronomers had no direct proof that any planets existed outside of the solar system. Sure, it seemed likely—the earliest speculation about exoplanets was way back in 1584— but it wasn't until the discovery of 51 Pegasi b that we actually could prove it.
Since then, we've made up for lost time: in the last 25 years, astronomers have discovered almost 2,000 other exoplanets, from tiny dwarfs half the mass of the moon to enormous gas giants, 29 times the size of Jupiter.
The latest infographic from Martin Vargic, the 17-year-old designer behind some of the most viral visualizations on on the 'Net, aims to put the staggering variety of astronomy's exoplanets in perspective. It contains more than 500 exoplanets, arranged on the x-axis according to average temperature, and on the y-axis by density of mass.
To create his infographic, Vargic used data from the exoplanet database, which lists statistics about the known universe's extra-solar planets. Of course, for the vast majority of planets, we don't have a really good idea of what they look like: our best images of them are often times just blurry blips of light or radiation.
So Vargic had to get creative. "I based the looks of each planet chiefly on its estimated radius and temperature, however other factors, such as density, age or stellar metallicity were also taken into consideration," he says. "The colors of gas giant planets were chosen to be as realistic as possible, reflecting the different cloud compositions of hotter gas giants."
Of course, as massive as this infographic is, it only covers about 25% of all known exoplanets. And with more exoplanets being discovered every year, it won't stay up-to-date for long. The universe is a vast place, and we've already proven that our solar system isn't nearly as special as we thought. How long until we can fit 500 life-harboring exoplanets on a poster too? Probably not as long as we think.